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docs(aio): fix aot TOC list items

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Kapunahele Wong 2017-04-19 11:43:46 -04:00 committed by Pete Bacon Darwin
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aio/content/guide/aot-compiler.md
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@ -6,14 +6,11 @@ Learn how to use ahead-of-time compilation.
@description
This cookbook describes how to radically improve performance by compiling _ahead-of-time_ (AOT)
during a build process.
{@a toc}
# Contents
* [Overview](guide/overview)
@ -22,31 +19,22 @@ during a build process.
* [Compile with AOT](guide/aot-compiler#compile)
* [Bootstrap](guide/aot-compiler#bootstrap)
* [Tree shaking](guide/aot-compiler#tree-shaking)
*[Rollup](guide/aot-compiler#rollup)
*[Rollup Plugins](guide/aot-compiler#rollup-plugins)
*[Run Rollup](guide/aot-compiler#run-rollup)
* [Rollup](guide/aot-compiler#rollup)
* [Rollup Plugins](guide/aot-compiler#rollup-plugins)
* [Run Rollup](guide/aot-compiler#run-rollup)
* [Load the bundle](guide/aot-compiler#load)
* [Serve the app](guide/aot-compiler#serve)
* [AOT QuickStart source code](guide/aot-compiler#source-code)
* [Workflow and convenience script](guide/aot-compiler#workflow)
*[Develop JIT along with AOT](guide/aot-compiler#run-jit)
* [Develop JIT along with AOT](guide/aot-compiler#run-jit)
* [Tour of Heroes](guide/aot-compiler#toh)
*[JIT in development, AOT in production](guide/aot-compiler#jit-dev-aot-prod)
*[Tree shaking](guide/aot-compiler#shaking)
*[Running the application](guide/aot-compiler#running-app)
*[Inspect the Bundle](guide/aot-compiler#inspect-bundle)
* [JIT in development, AOT in production](guide/aot-compiler#jit-dev-aot-prod)
* [Tree shaking](guide/aot-compiler#shaking)
* [Running the application](guide/aot-compiler#running-app)
* [Inspect the Bundle](guide/aot-compiler#inspect-bundle)
{@a overview}
## Overview
An Angular application consists largely of components and their HTML templates.
@ -54,15 +42,9 @@ Before the browser can render the application,
the components and templates must be converted to executable JavaScript by the _Angular compiler_.
<div class="l-sub-section">
<a href="https://www.youtube.com/watch?v=kW9cJsvcsGo" target="_blank">Watch compiler author Tobias Bosch explain the Angular Compiler</a> at AngularConnect 2016.
<a href="https://www.youtube.com/watch?v=kW9cJsvcsGo" target="_blank">Watch compiler author Tobias Bosch explain the Angular Compiler</a> at AngularConnect 2016.
</div>
You can compile the app in the browser, at runtime, as the application loads, using the **_just-in-time_ (JIT) compiler**.
This is the standard development approach shown throughout the documentation.
It's great but it has shortcomings.
@ -79,12 +61,8 @@ JIT compilation discovers them at runtime, which is late in the process.
The **_ahead-of-time_ (AOT) compiler** can catch template errors early and improve performance
by compiling at build time.
{@a aot-jit}
## _Ahead-of-time_ (AOT) vs _just-in-time_ (JIT)
There is actually only one Angular compiler. The difference between AOT and JIT is a matter of timing and tooling.
@ -93,7 +71,6 @@ with JIT it runs every time for every user at runtime using a different set of l
{@a why-aot}
## Why do AOT compilation?
*Faster rendering*
@ -117,47 +94,33 @@ The compiler is roughly half of Angular itself, so omitting it dramatically redu
The AOT compiler detects and reports template binding errors during the build step
before users can see them.
*Better security*
AOT compiles HTML templates and components into JavaScript files long before they are served to the client.
With no templates to read and no risky client-side HTML or JavaScript evaluation,
there are fewer opportunities for injection attacks.
{@a compile}
## Compile with AOT
Preparing for offline compilation takes a few simple steps.
Take the <a href='../guide/setup.html'>Setup</a> as a starting point.
A few minor changes to the lone `app.component` lead to these two class and HTML files:
<code-tabs>
<code-pane title="src/app/app.component.html" path="cb-aot-compiler/src/app/app.component.html">
</code-pane>
<code-pane title="src/app/app.component.ts" path="cb-aot-compiler/src/app/app.component.ts">
</code-pane>
</code-tabs>
Install a few new npm dependencies with the following command:
<code-example language="none" class="code-shell">
npm install @angular/compiler-cli @angular/platform-server --save
</code-example>
You will run the `ngc` compiler provided in the `@angular/compiler-cli` npm package
instead of the TypeScript compiler (`tsc`).
@ -167,13 +130,9 @@ instead of the TypeScript compiler (`tsc`).
Copy the original `src/tsconfig.json` to a file called `tsconfig-aot.json` on the project root,
then modify it as follows.
<code-example path="cb-aot-compiler/tsconfig-aot.json" title="tsconfig-aot.json" linenums="false">
</code-example>
The `compilerOptions` section is unchanged except for one property.
**Set the `module` to `es2015`**.
This is important as explained later in the [Tree Shaking](guide/aot-compiler#tree-shaking) section.
@ -185,7 +144,6 @@ to store the compiled output files in a new `aot` folder.
The `"skipMetadataEmit" : true` property prevents the compiler from generating metadata files with the compiled application.
Metadata files are not necessary when targeting TypeScript files, so there is no reason to include them.
***Component-relative template URLS***
The AOT compiler requires that `@Component` URLS for external templates and CSS files be _component-relative_.
@ -194,7 +152,6 @@ For example, an `'app.component.html'` URL means that the template file is a sib
While JIT app URLs are more flexible, stick with _component-relative_ URLs for compatibility with AOT compilation.
***Compiling the application***
Initiate AOT compilation from the command line using the previously installed `ngc` compiler by executing:
@ -203,24 +160,13 @@ Initiate AOT compilation from the command line using the previously installed `n
node_modules/.bin/ngc -p tsconfig-aot.json
</code-example>
<div class="l-sub-section">
Windows users should surround the `ngc` command in double quotes:
<code-example format='.'>
"node_modules/.bin/ngc" -p tsconfig-aot.json
</code-example>
Windows users should surround the `ngc` command in double quotes:
<code-example format='.'>
"node_modules/.bin/ngc" -p tsconfig-aot.json
</code-example>
</div>
`ngc` expects the `-p` switch to point to a `tsconfig.json` file or a folder containing a `tsconfig.json` file.
After `ngc` completes, look for a collection of _NgFactory_ files in the `aot` folder.
@ -232,37 +178,19 @@ and a JavaScript representation of the component's template.
Note that the original component class is still referenced internally by the generated factory.
<div class="l-sub-section">
The curious can open `aot/app.component.ngfactory.ts` to see the original Angular template syntax
compiled to TypeScript, its intermediate form.
The curious can open `aot/app.component.ngfactory.ts` to see the original Angular template syntax
compiled to TypeScript, its intermediate form.
JIT compilation generates these same _NgFactories_ in memory where they are largely invisible.
AOT compilation reveals them as separate, physical files.
JIT compilation generates these same _NgFactories_ in memory where they are largely invisible.
AOT compilation reveals them as separate, physical files.
</div>
<div class="alert is-important">
Do not edit the _NgFactories_! Re-compilation replaces these files and all edits will be lost.
Do not edit the _NgFactories_! Re-compilation replaces these files and all edits will be lost.
</div>
{@a bootstrap}
## Bootstrap
The AOT approach changes application bootstrapping.
@ -278,27 +206,17 @@ Switch from the `platformBrowserDynamic.bootstrap` used in JIT compilation to
Here is AOT bootstrap in `main.ts` next to the original JIT version:
<code-tabs>
<code-pane title="src/main.ts" path="cb-aot-compiler/src/main.ts">
</code-pane>
<code-pane title="src/main-jit.ts" path="cb-aot-compiler/src/main-jit.ts">
</code-pane>
</code-tabs>
Be sure to [recompile](guide/aot-compiler#compiling-aot) with `ngc`!
{@a tree-shaking}
## Tree shaking
AOT compilation sets the stage for further optimization through a process called _tree shaking_.
@ -317,10 +235,8 @@ Tree shaking can only target JavaScript code.
AOT compilation converts more of the application to JavaScript,
which in turn makes more of the application "tree shakable".
{@a rollup}
### Rollup
This cookbook illustrates a tree shaking utility called _Rollup_.
@ -331,46 +247,32 @@ It produces a final code _bundle_ that excludes code that is exported, but never
Rollup can only tree shake `ES2015` modules which have `import` and `export` statements.
<div class="l-sub-section">
Recall that `tsconfig-aot.json` is configured to produce `ES2015` modules.
It's not important that the code itself be written with `ES2015` syntax such as `class` and `const`.
What matters is that the code uses ES `import` and `export` statements rather than `require` statements.
Recall that `tsconfig-aot.json` is configured to produce `ES2015` modules.
It's not important that the code itself be written with `ES2015` syntax such as `class` and `const`.
What matters is that the code uses ES `import` and `export` statements rather than `require` statements.
</div>
In the terminal window, install the Rollup dependencies with this command:
<code-example language="none" class="code-shell">
npm install rollup rollup-plugin-node-resolve rollup-plugin-commonjs rollup-plugin-uglify --save-dev
</code-example>
Next, create a configuration file (`rollup-config.js`)
in the project root directory to tell Rollup how to process the application.
The cookbook configuration file looks like this.
<code-example path="cb-aot-compiler/rollup-config.js" title="rollup-config.js" linenums="false">
</code-example>
This config file tells Rollup that the app entry point is `src/app/main.js` .
The `dest` attribute tells Rollup to create a bundle called `build.js` in the `dist` folder.
It overrides the default `onwarn` method in order to skip annoying messages about the AOT compiler's use of the `this` keyword.
The next section covers the plugins in more depth.
{@a rollup-plugins}
### Rollup Plugins
Optional plugins filter and transform the Rollup inputs and output.
@ -389,89 +291,53 @@ Rollup then preserves the parts of `RxJS` referenced by the application
in the final bundle. Using it is straigthforward. Add the following to
the `plugins` array in `rollup-config.js`:
<code-example path="cb-aot-compiler/rollup-config.js" region="commonjs" title="rollup-config.js (CommonJs to ES2015 Plugin)" linenums="false">
</code-example>
*Minification*
Rollup tree shaking reduces code size considerably. Minification makes it smaller still.
This cookbook relies on the _uglify_ Rollup plugin to minify and mangle the code.
Add the following to the `plugins` array:
<code-example path="cb-aot-compiler/rollup-config.js" region="uglify" title="rollup-config.js (CommonJs to ES2015 Plugin)" linenums="false">
</code-example>
<div class="l-sub-section">
In a production setting, you would also enable gzip on the web server to compress
the code into an even smaller package going over the wire.
In a production setting, you would also enable gzip on the web server to compress
the code into an even smaller package going over the wire.
</div>
{@a run-rollup}
### Run Rollup
Execute the Rollup process with this command:
<code-example language="none" class="code-shell">
node_modules/.bin/rollup -c rollup-config.js
</code-example>
<div class="l-sub-section">
Windows users should surround the `rollup` command in double quotes:
<code-example language="none" class="code-shell">
"node_modules/.bin/rollup" -c rollup-config.js
</code-example>
Windows users should surround the `rollup` command in double quotes:
<code-example language="none" class="code-shell">
"node_modules/.bin/rollup" -c rollup-config.js
</code-example>
</div>
{@a load}
## Load the bundle
Loading the generated application bundle does not require a module loader like SystemJS.
Remove the scripts that concern SystemJS.
Instead, load the bundle file using a single `<script>` tag **_after_** the `</body>` tag:
<code-example path="cb-aot-compiler/src/index.html" region="bundle" title="index.html (load bundle)" linenums="false">
</code-example>
{@a serve}
## Serve the app
You'll need a web server to host the application.
@ -481,53 +347,31 @@ Use the same `lite-server` employed elsewhere in the documentation:
npm run lite
</code-example>
The server starts, launches a browser, and the app should appear.
{@a source-code}
## AOT QuickStart source code
Here's the pertinent source code:
<code-tabs>
<code-pane title="src/app/app.component.html" path="cb-aot-compiler/src/app/app.component.html">
</code-pane>
<code-pane title="src/app/app.component.ts" path="cb-aot-compiler/src/app/app.component.ts">
</code-pane>
<code-pane title="src/main.ts" path="cb-aot-compiler/src/main.ts">
</code-pane>
<code-pane title="src/index.html" path="cb-aot-compiler/src/index.html">
</code-pane>
<code-pane title="tsconfig-aot.json" path="cb-aot-compiler/tsconfig-aot.json">
</code-pane>
<code-pane title="rollup-config.js" path="cb-aot-compiler/rollup-config.js">
</code-pane>
</code-tabs>
{@a workflow}
## Workflow and convenience script
You'll rebuild the AOT version of the application every time you make a change.
@ -539,14 +383,10 @@ Open a terminal window and try it.
<code-example language="none" class="code-shell">
npm run build:aot
</code-example>
{@a run-jit}
### Develop JIT along with AOT
AOT compilation and rollup together take several seconds.
@ -558,23 +398,17 @@ The same source code can be built both ways. Here's one way to do that.
* Restore the SystemJS scripts like this:
<code-example path="cb-aot-compiler/src/index-jit.html" region="jit" title="src/index-jit.html (SystemJS scripts)" linenums="false">
</code-example>
Notice the slight change to the `system.import` which now specifies `src/app/main-jit`.
That's the JIT version of the bootstrap file that we preserved [above](guide/aot-compiler#bootstrap).
Open a _different_ terminal window and enter `npm start`.
<code-example language="none" class="code-shell">
npm start
</code-example>
That compiles the app with JIT and launches the server.
The server loads `index.html` which is still the AOT version, which you can confirm in the browser console.
Change the address bar to `index-jit.html` and it loads the JIT version.
@ -589,22 +423,16 @@ return to the AOT version in the default `index.html`.
Now you can develop JIT and AOT, side-by-side.
{@a toh}
## Tour of Heroes
The sample above is a trivial variation of the QuickStart application.
In this section you apply what you've learned about AOT compilation and tree shaking
to an app with more substance, the [_Tour of Heroes_](tutorial/toh-pt6) application.
{@a jit-dev-aot-prod}
### JIT in development, AOT in production
Today AOT compilation and tree shaking take more time than is practical for development. That will change soon.
@ -618,21 +446,14 @@ The JIT and AOT apps require their own `index.html` files because they setup and
Here they are for comparison:
<code-tabs>
<code-pane title="aot/index.html (AOT)" path="toh-pt6/aot/index.html">
</code-pane>
<code-pane title="src/index.html (JIT)" path="toh-pt6/src/index.html">
</code-pane>
</code-tabs>
The JIT version relies on `SystemJS` to load individual modules.
Its scripts appear in its `index.html`.
@ -645,21 +466,13 @@ JIT and AOT applications boot in much the same way but require different Angular
The key differences, covered in the [Bootstrap](guide/aot-compiler#bootstrap) section above,
are evident in these `main` files which can and should reside in the same folder:
<code-tabs>
<code-pane title="main-aot.ts (AOT)" path="toh-pt6/src/main-aot.ts">
</code-pane>
<code-pane title="main.ts (JIT)" path="toh-pt6/src/main.ts">
</code-pane>
</code-tabs>
***TypeScript configuration***
JIT-compiled applications transpile to `commonjs` modules.
@ -668,105 +481,65 @@ AOT requires its own TypeScript configuration settings as well.
You'll need separate TypeScript configuration files such as these:
<code-tabs>
<code-pane title="tsconfig-aot.json (AOT)" path="toh-pt6/tsconfig-aot.json">
</code-pane>
<code-pane title="src/tsconfig.json (JIT)" path="toh-pt6/src/tsconfig.1.json">
</code-pane>
</code-tabs>
<div class="callout is-helpful">
<header>
@Types and node modules
</header>
In the file structure of _this particular sample project_,
the `node_modules` folder happens to be two levels up from the project root.
Therefore, `"typeRoots"` must be set to `"../../node_modules/@types/"`.
<header>
@Types and node modules
</header>
In the file structure of _this particular sample project_,
the `node_modules` folder happens to be two levels up from the project root.
Therefore, `"typeRoots"` must be set to `"../../node_modules/@types/"`.
In a more typical project, `node_modules` would be a sibling of `tsconfig-aot.json`
and `"typeRoots"` would be set to `"node_modules/@types/"`.
Edit your `tsconfig-aot.json` to fit your project's file structure.
In a more typical project, `node_modules` would be a sibling of `tsconfig-aot.json`
and `"typeRoots"` would be set to `"node_modules/@types/"`.
Edit your `tsconfig-aot.json` to fit your project's file structure.
</div>
{@a shaking}
### Tree shaking
Rollup does the tree shaking as before.
<code-example path="toh-pt6/rollup-config.js" title="rollup-config.js" linenums="false">
</code-example>
{@a running-app}
### Running the application
<div class="alert is-important">
The general audience instructions for running the AOT build of the Tour of Heroes app are not ready.
The following instructions presuppose that you have cloned the
<a href="https://github.com/angular/angular.io" target="_blank">angular.io</a>
github repository and prepared it for development as explained in the repo's README.md.
The general audience instructions for running the AOT build of the Tour of Heroes app are not ready.
The following instructions presuppose that you have cloned the
<a href="https://github.com/angular/angular.io" target="_blank">angular.io</a>
github repository and prepared it for development as explained in the repo's README.md.
The _Tour of Heroes_ source code is in the `public/docs/_examples/toh-6/ts` folder.
The _Tour of Heroes_ source code is in the `public/docs/_examples/toh-6/ts` folder.
</div>
Run the JIT-compiled app with `npm start` as for all other JIT examples.
Compiling with AOT presupposes certain supporting files, most of them discussed above.
<code-tabs>
<code-pane title="src/index.html" path="toh-pt6/src/index.html">
</code-pane>
<code-pane title="copy-dist-files.js" path="toh-pt6/copy-dist-files.js">
</code-pane>
<code-pane title="rollup-config.js" path="toh-pt6/rollup-config.js">
</code-pane>
<code-pane title="tsconfig-aot.json" path="toh-pt6/tsconfig-aot.json">
</code-pane>
</code-tabs>
Extend the `scripts` section of the `package.json` with these npm scripts:
Copy the AOT distribution files into the `/aot` folder with the node script:
@ -775,30 +548,18 @@ Copy the AOT distribution files into the `/aot` folder with the node script:
node copy-dist-files
</code-example>
<div class="l-sub-section">
You won't do that again until there are updates to `zone.js` or the `core-js` shim for old browsers.
You won't do that again until there are updates to `zone.js` or the `core-js` shim for old browsers.
</div>
Now AOT-compile the app and launch it with the `lite-server`:
<code-example language="none" class="code-shell">
npm run build:aot && npm run serve:aot
</code-example>
{@a inspect-bundle}
### Inspect the Bundle
It's fascinating to see what the generated JavaScript bundle looks like after Rollup.
@ -812,24 +573,18 @@ Install it:
npm install source-map-explorer --save-dev
</code-example>
Run the following command to generate the map.
<code-example language="none" class="code-shell">
node_modules/.bin/source-map-explorer aot/dist/build.js
</code-example>
The `source-map-explorer` analyzes the source map generated with the bundle and draws a map of all dependencies,
showing exactly which application and Angular modules and classes are included in the bundle.
Here's the map for _Tour of Heroes_.
<a href="assets/images/cookbooks/aot-compiler/toh6-bundle.png" target="_blank" title="View larger image">
<figure class='image-display'>
<img src="assets/images/cookbooks/aot-compiler/toh6-bundle.png" alt="TOH-6-bundle"></img>
</figure>
</a>
<figure class='image-display'>
<img src="assets/images/cookbooks/aot-compiler/toh6-bundle.png" alt="TOH-6-bundle"></img>
</figure>
</a>